Help, Hino 700 is filling the oil sump with diesel

[P34chPlum]

my buddy's annoyed with his Hino 700 (E13C engine), and he doesn't know what to do. He just had a new fuel pump put in, and now diesel is somehow getting into the oil sump.
The return line seems to have way too much pressure, and fuel actually splashes out of the pump when he revs it.

He's wondering if it could be the injector pump timing, but we're both a little stumped. Has anyone seen this before? Any ideas on what's going on?

 

[Longhaullife]

I'm no expert, but it sounds like there might be a problem with the seals in the injector pump, or maybe there's some pressure building up because of a blocked return line. Timing might also be a factor, but honestly, your first step should be to check for any leaks in the pump seals